Why is the ΔG of ATP hydrolysis in the cell about twice as great as the ΔG of ATP hydrolysis in a test tube under standard conditions?
A) A cell is an open system, whereas a test tube is a closed system.
B) ATP hydrolysis in a test tube releases more heat than ATP hydrolysis associated with cellular metabolism.
C) Reactant and product concentrations in the test tube are different from those in the cell.
D) ATP hydrolysis in cells is catalyzed by enzymes, whereas the reaction in a test tube occurs spontaneously.

Question

Quizplus · Accepted Answer

The ΔG of ATP hydrolysis is dependent on the concentrations of reactants and products. In the cell, the concentrations of reactants and products are not at standard conditions due to the presence of other molecules and metabolic processes. Therefore, the ΔG of ATP hydrolysis in the cell is about twice as great as in a test tube where the concentrations are at standard conditions.

Why Is the ΔG of ATP Hydrolysis in the Cell